<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>下拉菜单</title>
	<script src="jquery-3.3.1.js"></script>
	<script src="bootstrap.bundle.js"></script>
	<script src="bootstrap.js"></script>
	<link rel="stylesheet" href="bootstrap.css">
	<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.2.0/css/all.css">
</head>

<body>
	<div class="dropdown">
		<a href="#" class="btn  btn-danger" data-toggle="dropdown">下拉菜单<i class="fas fa-angle-down"></i></a>
		<ul class="dropdown-menu">
			<li><a herf="#">菜单项1</a></li>
			<li><a href="#">菜单项2</a></li>
			<li><a href="#">菜单项3</a></li>
		</ul>
	</div>
</body>
</html>
